The etiology of uveal melanoma is unknown. A case-control study of uveal melanoms is proposed to explore possible associations between environmental agents and other possible risk factors with the occurrence of this potentially lethal disease. This study will expand our knowledge of uveal melanoma etiology, which to date is essentially unexplored. Cases are patients with uveal melanoma involving the choroid and/or ciliary body. Two sources of cases and controls will be used and the study will have two parts: Part 1) Incident cases identified at the Massachusetts Eye and Ear Infirmary (MEEI) with siblings as controls, and Part 2) Incident cases in a defined geographic area, the New England States, with people from the general population matched on age within 5 years, and sex, as controls. Nonwhites will not be included since the disease is rare in non-whites and no meaningful analyses could be performed on this small sample of cases. An interview with cases and controls lasting 30-40 minutes will be conducted over the telephone by trained interviewers. Subjects covered in the interview include sociodemographic factors, occupational and other exposures such as chemicals, toxic agents, sunlight and radiation, ocular exposures or conditions, personal habits, and hormonal factors. Prior to the interview, interviewers will not be aware of the case or control status of subjects. Coding of the interviews will be done in masked fashion with respect to case control status. This study will determine whether such factors are associated with an increased risk of uveal melanoma and will estimate the magnitude of such risk. The analysis will involve the comparison of the frequency of various exposures among the cases to the frequency of those exposures among the controls. Analytic techniques to be employed include the analysis of matched case-control studies calculating the Mantel-Haenszel estimate of relative risk and also the conditional logistic regression analysis. Such a case-control study will be the first known epidemiologic study to examine a broad range of possible etiologic factors for uveal melanoma using incident cases in a prospective fashion, which in one part of the study will comprise most of the incident cases in a defined geographic area.